Telephone-call distribution system



June 2, 192

G. DEAKIN TELEPHONE CALL DISTRIBUTION SYSTEM Filed Nov. 29 1922 Patented June 2, 1925.

UNITED STATES Parent orr cs.

GERALD IDLE-AKIN, or ANTWERP, anaemia, assreivoa 'ro'wnsrnnn nnncrmc core PANY, INCORPORATED, on NEW YORK, N, Y.) a oonronnrron or new YORK.

TELEPHONE-CALL DISTE-EB'UKION Application filed November 29, 1922. Serial No. 603,923.

To all whom it may concern:

Be it known that I, GERALD DEAKIN, a citizen of the" United States, residing at Antwerp, Belgium, have invented certain new and useful Improvements in Telephone Call Distrilmtion Systems, of which the following is a full, clear, concise, and exact description. y

This invention relates to machine call distributing systems and more particularly to an improved and simplified arrangement of circuits and apparatus whereby a calling line is extended to a connecting circuit over a plurality of automatically operating line finder switches.

The principal feature of the invention resides in the employment of a single test re lay in the circuit of the first line finder switch and more particularly to the use of a single relay in association with a first line finder switch wherein such relay performs the combined function of testing for and stopping. the brushes on the calling line ter-- minals and holding the calling line busy when necessary, this as shown, being accomplished both under control of the line relay and under control'of the second line finder circuit.

Another feature of the invention is that the cut-off relay before operation provides a low resistance path for the second line finder test circuit which is increased when said cutoff relay operates thereby reducing current consumption.

Another feature of the invention resides in such an organization of circuits that double tests at the first line finder are taken care of at the second line finder, thereby sin'iplifying the apparatus used at the first line finder as such doubletests under those conditions are not objectionable.

The operation of the circuit of the invention will be understood from the following description when read in connection with the drawing which represents a subscribers line circuit, a first line finder circuit and so much of the second line finder circuit as is necessary for a clear understanding of the invention. .For a complete disclosure of a system to which the present invention is applicable reference is made to U. S. Patent No. 1,482,618 to L, Polinkowsky et al, granted February 25, 1924.

When the subscriber S removes his receiver a circuit is established for the line relay 1, right inner back contact of cut-off relay 2 over the subscribers line, the substationapparatus and to groundat the left back contact of relay 2. The line relay 1 operates in this circuit and closes its front contacts thcreby autting potential on the test terminal 16 from grounded battery, left armature and front contact' of relay 1 and resistance 2% in series with the test terminal. A potential is also placed on line terminal from grounded abattery, through one winding of relay 2 in parallel with anoninductive resistance and right front contact of relay 1; p I

Also when line relay 1 closed its front contacts a circuit for the common starting relay 3 was established from grounded bat-- tcry, left armature and front contact of relay land the winding of relay 3 to ground. Power magnet 4 is now energized to start the brushes hunting for the calling line in a.

thereby opening the circuit for the power magnet a at the left-hand back contact of relay 6. The power magnet 4i is deenerg'ized and the brushes come to rest on the calling line. Test relay 6 in operating also shunts its high resistance winding 26 by a low resistance winding 27 over a circuit from ground, winding of common starting relay 7 and right-hand front contact of relay 6 and its left-hand winding 27, thus lowering the potentialon the test-terminal 16 and making the calling line busy to other hunting finders. c

When the circuit through relay 7 was closed this relay energized and closed at-its front contact a circuit for the energiZat-ion of group line relay 8 through sequence switch contact 21 in position 1. Relay 8- operated and closed a circuit at its front contact for the energization of power magnet 9 from grounded battery, coil of magnet '9 and back contact of group test relay 10.

. inductive resistance 28, terminal of the iii calling line, right-hand armature and contact of relay 1, left-hand winding of relay 2 in parallel with non-inductive resistance 25 to grounded battery. Group test relay 10 energizes in this circuit and opens at its back contact the circuit forpower magnet 9 at which the brushes come to rest on the terminals of the first line finder connected to the calling line. Test relay 10 in making its front contact shunts its right-hand high resistance winding by its left-hand low resistance winding, thus lowering the potential at the terminal 19 and making it busy for all other hunting second line finders. Cut-oft relay 2 also energizes in this circuitand first closes its right-hand front contact 11 and immediately thereafter disconnects at its right back contact 12 the line relay 1 from the line. The reason for causing con tact 11 to make before 12 breaks is to prevent the opening of the above traced circuit and the consequent deenergization of relay (3, when relay 1 deenergizes. When the contact 11 of'relay 2 was closed a circuit was prepared for the t iillSfGl' of the above test relay circuit through both windings of relay 2 in series which circuit being of greater esistance due to the addition of the extra relay winding is efiective on the release of relay 1 to reduce the holding current. The removal of potential from terminal 16 by the release of relay 1 causes the deenergization and release of relay 7 but relay 6 remains energized by virtue of its right-hand winding which is contained in the test circuit before traced. lVhen relay 10 energized, as above described, a circuit was also closed from battery, through the power magnet 01 sequence switch 30, front contact of relay 10, front contact of relay 8 to ground, in which circuit the magnet operated to advance the sequence switch out of position 1. \Vhen the sequence switch leaves position 3, the circuit above .traced through the group test relay 10 is broken at sequence switch contact 20, but cut-oil relay 2 is main tained energized in circuits (not shown) over other contacts of sequence switch cam 31 throughout the maintenance of the connection. V g

It will be noted that while the energization of test relay (3 makes the calling line busy to other hunting line'finders it does not prevent double connections due to simultaneous testing. These are purposely permitted as in this way it is not necessary to have closely marginal relays in the first line finder circuit, such double tests at the first line finder being easily cared for by the second line finder circuit in the following manner. 1

Assume that two first line finders simultaneously pick up the calling line. In the ordinary course of events one of these will be picked up by a second line finder before the other in which case the energization of relay 2 and the consequent release of relay 1 will release the test relay (3 connected to the other first line finder as its high resistance right-hand winding is still open due to the fact that a second line finder has not yet contacted with its terminal 19 to supply ground to complete the holding circuit for the test relay.

Further, let us assume a more remote case in which a doublertest occurs at both the first and second line finders, that is to say, when two first line finders simultaneously stop on a calling line and then two second line finders simultaneously stop on these two first line finders. In this case one or both of the group test relays 10 of the second line finders thus stopped will be deenergized when the sequence switch contact 22 opens by the switch moving out of position 1, for the reason that the potential of terminal 19 is lowered to such a degree by the opening of the high resistance right-hand winding of relay 10 that two properly adjusted marginal relays will not hold in the circuit. This sequence of events will continue until one second line finder contacts with a busy first line finder in advance of the others.

hat is claimed is:

1.'In a telephone system, a telephone line,

a line finder switch for extending said line,

a relay associated with said line finder switch arranged to respond to a test inclicating the arrival of said line finder on the terminals of said line, and means under the direct control of said relay for thereupon stopping the movement of said line finder and for thereafter marking said line as busy.

2. In a telephone system, a telephone line having a line relay and a cut-off relay, a first line finder switch for extending said line, a second line finder switch for further extending said line, a relay associated with said first line finder switch arranged to respond to a test indicating the arrival of said first line finder on the terminals of said line, and means under the direct control of said relay for thereupon stopping the movement of said first line finder and thereafter marking said line as busy, said line relay havingmeans to control said test re lay to maintain said busy indication.

3. In a telephone system, a te'lcplione line having a line relay and a cut-off relay, a

first line finder switch tor'extending said spond toa test indicating the arrival of said first line finder on the terminals of said line, and means controlled by said relay for thereupon stopping the movement o'l said first line finder and thereafter marking said line as busy, said line relay having means to control said test relay to maintainsaid busy indication until said second line finder has further extended said line, and means in said second line finder for energizing said cutoli' relay.

i. In a telephone system, a telephone line having a line relay and a cut-o'fi' relay, a first line finder switch for extending said line, a second line finder switch for further extending said line, a relay associated with said first line finder switch arranged to respond to atest indicating the arrival of said first line finder on the terminals of said line, and means controlled by said relay for thereupon stopping the movement or said first line finder and thereafter marking said line as busy, said line relay having means to control said test relay to maintain said busy indication until said second line finder has further extended said line and means in said second line finder for energizing said cut-ofi relay and thereafter controlling said test relay to maintain said busy indication.

in a telephone system, a telephone line having); a line relay and a cut-ofi' relay, a :13 line finder switch for extending said no line, a secondline finder switch for further extending said line, a relay associated with said first line finder switch arranged to respond to a test indicating the arrival of said first line finder on the terminals of said line, and means controlled by said relay for thereupon stopping the movement of said first line finder and thereafter n'iaij'king said line as busy, said line relay having means to control said test relay to maintain said busy indication until said second line finder further extended said line and means in said second line finder for energizing said cut-off relay, said cut-ofi' relay. having means for increasing the resistance of its own circuit so as to decrease the current drain in this circuit during the maintenance oi a connection.

(3. In a telephone system, a telephone line having a line relay and a cut-off relay, a first line finder switch for extending said line, a second line finder switch for ii'urther extending said line, a relay associated with said first line finder switch arranged to resound to a test indicatingthe arrival of said first line finder on the terminals of said line, and means controlled by said relay for control sai 'i iirdication'ui' V 5 further extended "said *line and in said second line finder eat-on relay and there stopping the 1noyenren-tlo l said efr andtliereaitern Q king said y, sai-d'line relay'havi gineans to st relay to maintain said busy il, said secondline 'finde- 'or energizing said er controlling said test relay to maintain said busy indication, said-'cut-ofi relay having means for increasing the resistance of its own circuit so as to decrease the current drain in this circuit during the maintenance of a connection;

7. In a telephone system, a telephone line having a line relay and a cut-off relay, a first line finder switch for extending said line, a second line finder switch for further extending said line, a relay associated with said first line finder switch arranged to respond to a test indicating the arrival of said first line finder on the terminals of said line,

and means controlled by said relay for thereupon stopping the movement of said first line-finder and thereafter marking saidline as busy, said line relay having means to control said test relay to maintain said busy indication until said second line finder has further extended said line, means in said second line finder for energizing said cut-oil relay and thereafter controlling saidtest relay to maintain said busy indication, said cutofi relay having means for increasing the resistance of its own circuit so as to decrease the current drain in this circuit during the maintenance of a connection, to prevent an other second line finder from stopping on the line extended by said first line finder.

8. In a telephone system, a telephone line appearing in the terminals of a plurality of finders which have stopped on said line, and

means responsive to the simultaneous finding of a plurality of said first finders by a plurality of said secondary finders for preventing any one of said last mentioned sec ondary finders from. remaining on the terminals of any one of said first finders.

9. In a telephone system, a telephone line appearing in the terminals of a plurality of line finders, means responsive to the initiation of a call on said line for starting a plurality of said line finders, means responsive to the simultaneous finding of said line by a plurality of said finders for stopping said finders on said line, means under control of each of said finders for starting a plurality of secondary finders insearch of said first finders which have stopped on said 1i11e,

means responsive to the simultaneous finding, of a plurality of said first finders by a plurality of said secondary finders for preventing any one of said last mentioned secondary finders from remaining on the terminals of any one of said first finders, and

'means responsive to the finding ofone of said first finders by one of said secondary finders for releasing all but the one said first finder on the terminals of which said seo- 10 ondary finder has stopped. V

In Witness whereof, I hereunto subscribe my name this 10th day of November A. D., 1922. 1 a

GERALD DEAKIN. 

